Tumors developing in minorities appear to be more aggressive and may be due to genetic differences among different groups. The change from the non-metastatic to the metastatic phenotype represents a critical step in the pathology of any cancer. While investigations have identified markers that could be involved in metastasis, the specific mechanisms that lead to a more invasive phenotype have not been discerned. In the leopard frog, Rana pipiens, a model system exists by which invasive behavior can be controlled by a direct simple manipulation of an environmental factor (temperature). The Lucke tumor, a herpes virus (RaHV-1) induced renal adenocarcinoma of Rana pipiens, expresses seasonal differential invasive behavior depending upon temperature. Metastatic colonies are observed in young frogs only after exposure to summer's elevated temperatures. Fragments of primary tumor collected from wild-caught frogs co-cultured with normal frog tissues invade the tissues at temperatures above 23 degrees C, but will not invade at temperatures below 23 degrees C. Additionally, primary tumor fragments will "grow" for extended periods in anterior eye chambers of immunosuppressed frogs and new tumors can be induced by injection of purified RaHV-1 into taitbud stage embryos. A variably aneuploid "immortal" cell line, PNKT-4B, derived from tumor tissue shows a similar temperature-dependent invasive phenotype and would be an excellent model system to investigate possible differential gene expression in metastatic and non-metastatic tumors. One of the genes that will be examined will the TERT protein associated with telomerase activity. It has been shown in other cancers from humans and other organisms that telomerase activity is high in most cancers and could be used as a diagnostic marker in certain neoplasias. Recent studies have revealed that the PNKT-4B cells express specific extracellular matrix-degrading enzymes and cytokines when cells are maintained at the invasive-permissive temperature of 28 degrees C. Using these studies as a starting point, the proposed research will use microarray technology to investigate genes differentially expressed in response to temperature changes in primary tumors (cells isolated from wild-caught frogs) and the PNKT-4B cell line. Additionally, telomerase activity and the expression of specific telomerase-associated proteins will be examined to monitor the degree of metastasis in primary tumors and the PNKT-4B cultured cells at the invasive-restrictive (18 degrees C) and invasive-permissive (28 degrees C) temperatures.